This is the first English biography of Gaston Bachelard, a philosopher who bridged the worlds of science and imagination. Raised in rural France, Bachelard served in the First World War, worked for the post office and pursued degrees in science and philosophy while teaching in his local school. His journey led to a professorship at the Sorbonne, where he influenced many prominent postwar French thinkers. Known as both a philosopher of science and author of works on the imagination inspired by the elements - earth, air, fire and water - Bachelard needed to negotiate a constant tension between science and poetry, calculation and dream. This biography provides a complete portrait of Bachelard, illuminating his struggles with the nature of knowledge itself.